Snakes can be classified into non-venomous and venomous types. A non-venomous snakebite typically leaves one or two rows of fine tooth marks on the skin, with mild local pain and possible blister formation, but no systemic reaction. A venomous snakebite usually results in a pair of larger, deeper fang marks, through which venom is injected into the body, causing severe poisoning. Snake venom is a complex mixture containing various toxic proteins, tissue-dissolving enzymes, and peptides, and can be categorized into neurotoxins and hemotoxins. Based on the nature of their venom, venomous snakes can generally be divided into three categories: those with primarily neurotoxic venom, such as the banded krait and many-banded krait; those with primarily hemotoxic venom, such as the green pit viper and viper; and those with mixed venom, such as the king cobra and cobra.
Clinical Manifestations
After a venomous snakebite, fang marks are typically present at the bite site, accompanied by pain and swelling. Swelling can spread rapidly, with lymph node enlargement, the appearance of blood blisters, ecchymosis, and even localized tissue necrosis. Patients may experience fever, chills, restlessness, dizziness, slurred speech, muscle tremors, nausea, vomiting, flaccid paralysis of the limbs, respiratory distress, and abnormal sensations around the mouth. Ultimately, circulatory and respiratory failure may occur. Some patients may develop pulmonary edema, hypotension, and arrhythmias due to extensive capillary leakage, along with skin and mucosal bleeding, bleeding from wounds, hematuria, oliguria, renal insufficiency, and multiple organ failure. Laboratory findings may include thrombocytopenia, decreased fibrinogen levels, prolonged prothrombin time, elevated serum creatinine, increased creatine phosphokinase, and the presence of myoglobinuria.
Treatment
Facilitating the rapid elimination of venom and preventing its absorption and spread are key to treatment. When the type of snakebite cannot be identified, treatment should initially follow the emergency protocol for venomous snakebite, with close monitoring of the patient’s condition.
Emergency Measures
Running should be avoided after a venomous snakebite. A tourniquet, such as a cloth band, should be applied to the proximal end of the affected limb to help limit venom spread, and manual pressure can be used around the wound to expel venom. The tourniquet should be loosened every 30 minutes for 1–2 minutes each time to avoid impairing circulation and causing tissue necrosis. The wound should be irrigated with 0.05% potassium permanganate solution or 3% hydrogen peroxide solution. Any remaining snake fangs should be removed. For deep wounds, a small incision can be made through the dermis, or a flat skin puncture can be performed at the swollen area with a triangular needle, followed by cupping or suction with a breast pump to help extract some of the venom. For bites from snakes with hemotoxic venom, coagulation may be severely impaired within a short time, so wounds that continue to bleed should not be incised.
Proteolytic enzymes can directly neutralize snake venom. A dose of 2,000–6,000 IU can be mixed in 10–20 ml of 0.05% procaine injection or sterile water for injection and administered via regional infiltration around or proximal to the wound. A second dose may be given 12–24 hours later if necessary.
Antivenom Therapy
Some fresh herbal medicines have shown efficacy in treating venomous snakebites. Antivenoms include both monovalent and polyvalent types. For identified snake species, monovalent antivenom is preferable due to its higher specificity; otherwise, polyvalent antivenom is used. An allergy test should be conducted before administration; if positive, desensitization should be performed.
Additional Therapies
Standard use of tetanus antitoxin and antibiotics is recommended to prevent infection. Appropriate interventions should be implemented for bleeding tendencies, shock, and renal insufficiency, and plasma or red blood cell transfusions may be required. For patients with respiratory distress, tracheotomy or mechanical ventilation may be necessary to support breathing while protecting organ function. Clinical monitoring should pay special attention to changes in the nervous, cardiovascular, and hematologic systems, as distinguishing between neurotoxic and hemotoxic effects can guide treatment decisions. Additionally, the use of central nervous system depressants, muscle relaxants, epinephrine, and anticoagulants should be avoided during treatment.